What is her birth information? I've just recently been looking into a Henry E. McWithey (1839-1929) that married into my Smith line, and he lists his father's birth as VT and mothers birth at NY.
He lives in Chippewa Co., WI which is not far from the Monroe Co. boarder from what I can tell. My descendants are mainly in the Monroe Co., WI area.
He may be related in some way, a brother or son to your Betsy's husband, J.G. On one census I found my Henry had a brother James b. 1872. That could be the J.G., just throwing it out there.
Just thought I'd throw this out there.